Lab Analysis of Lipids and Lipoproteins (Exam 2)

What is a cholesterol ester?

Cholesterol + fatty acid

The ______ method is the cholesterol assay of choice.

enzymatic

What colored compounds can interfere with enzymatic cholesterol assays?

Bilirubin, ascorbic acid, hemoglobin

Step 1 of an enzymatic cholesterol assay

Cholesterol Esters --> Cholesterol + Fatty Acids

Step 2 of enzymatic cholesterol assay

Cholesterol + O2 --> Cholesten-3-one + H2O2

Step 3 of enzymatic cholesterol assay

2H2O2 + 4 Aminoantipyrine + Phenol --> Quinoneimine + 2H2O

The product of an enzymatic cholesterol assay (quinoneimine) is measured via ______.

spectrophotometry

______ can be assessed via different procedures, but they all start the same.

Triglycerides

Step 1 of triglyceride enzymatic assay

Triglyceride + Water --> Glycerol + Fatty Acids

Step 2 of triglyceride enzymatic assay

Glycerol + ATP --> Glycerol-1-Phosphate + ADP

Step 3 of triglyceride enzymatic assay

Glycerol-1-Phosphate + O2 --> Dihydroxyacetone Phosphate + H2O2

Step 4 of triglyceride enzymatic assay

H2O2 + 4-aminoantipyrine + ESPA --> Quinoneimine Dye + H2O2

This product is measured via ______.

spectrophotometry

Small amounts of circulating free ______ is present in serum, which can cause triglyceride level elevation unless corrected.

glycerol

What is the desirable triglyceride level?

<150 mg/dL

Early methods for HDL-cholesterol assays use pre-treatment ______ and ______ methods to remove all non-HDL lipoproteins.

centrifugation, precipitation

After this pre-treatment, the ______ is analyzed for HDL.

supernatant

Non-HDL plasma value = ______.

total cholesterol - HDL

The direct/homogenous method for HDL-cholesterol is one of the most common, involving ______ of non-HDL lipoprotein.

masking

Non-HDL

LDL, IDL, VLDL, chylomicrons and remnants

This masking can be done with ...

- Antibodies

- Polymers

- Enzymes

The direct HDL-cholesterol method should be used with caution when there are extremely high plasma ______ levels.

triglyceride

Increased LDL is associated with ______.

CVD risk

the LDL reference method is known as ______.

Beta-quantification

Beta-quantification requires ______ overnight.

centrifugation

Before this, LDL-cholesterol was measured indirectly by using the ______.

Friedwald Equation

To use the Friedwald Equation, the serum sample must be separated into what fractions?

- Total cholesterol

- HDL cholesterol

- Triglycerides

Friedwald Equation

LDL-C = ______

TC - HDL - (TG/5)

The Friedwald Equation estimates LDL-C when triglyceride levels are ______ mg/dL.

<400

The direct/homogenous LDL-C method ______ all non-LDL for measurement.

masks

Increased serum hs-CRP is associated with risk of ______.

future CVD events

hs-CRP is an early ______ (very dramatic incrase with inflammation).

positive APP